Preparation of thiazoles



9atented Mar. 19, 1946 human STATES PATENT asserts examination on 'rnmzorns 'Joim. Kenson Simona, Toledo. iihio. assigner, by to Libbey-Qwens-Fcrd Glass @ompany... a corporation oi @hio No Drawing. Application ltngnat 7,11%2,

Serial No. 453,93?

a claims. (oi. sea-sea) mesne assignments,

The invention relates to the preparation of thiazoles which are useful in the preparation of ynthetic resins and which are new carbon compounds.

Thiazoles have not been known heretofore to produce thermosetting resins by reaction with aldehydes. The invention is based upon the discovery thatcertain types of thiazoles react with aldehydes to form thermosetting resins.

The principal object of the invention is the preparation of thiazoles that react with aldehydes to form synthetic resins. More specific objects and advantages are apparent from the description, which discloses and illustrates the invention invention. which do react with aldehydes to form thermosetting resins, are substances having the general formulae and m-m-B-APR in which A1 and A: are bivalent radicals selected from the group consisting of.

the step of carrying out a Friedel-Craits reaction between an aromatic compound, and an aeyi halide. By the use of that'step, it is possible to prepare a dihalo diketonewhich is then reacted with thiourea. The product of the latter reaction is a hydrohalide which may be treated with a base in order to set free the novel carbon com= pound that is capable oi're'acting with aldehydes to produce thermosetting resins.

v Such a method may be'carried out'by causing a Friedel-Crafts reaction to take place. between a substance having the general formula t cn-c R X:

in which X1 and X2 are selected from the group consisting of Cl and Br, and R isselected from the group consisting of H, methyl, ethyl, n-propyl, isopropyl, phenyl and benzyl, and a substance selected from the group consisting of benzene, a

substituted benzene having not more than four monovalent substituents of which not more than three are methyl and not more than two are selected from the group consisting of methoxy and ethoxy, and substances having the general formulae Yi-O-Ys, and

ri-o- (CHs-CHz-O) r-Y:

in which Y1 and Y: are selected from the group consisting of phenyl and substituted phenyl having not more than two monovalent substituents selected from the group consisting of methoxy and ethoxy; and a: is an integer not greater than 6, and then reacting with thioureathe dihalo diketone so obtained. In the Friedel-Crafts re-' action, in the first step of such a method, 2 mols of the halogenated acyl halide react with each I so u is an integer not greater than 12; R1 and R2 are monovalent radicals selected from the group consisting of H, methyl, ethyl, n-propyl, isopropyl, phenyl and benzyl; B is a bivalent radicalselected from-the group consisting of phenylene, substituted phenylene having not more than four monovalent substituents of which not more than three are methyl and not more than two are selected from the group consisting of methoxy and ethoxy, --T1--=O-is-=, and

-T1--0=- (CHa-CHe-O) 2-42- T1 and 1': are bivalent radicals selected from the group consisting of phenyiene and substituted phenylene having not more than two monovalent substituents selected from the group consisting of methoxy and ethoxy; and a: is an integer not reater than 6.

A highly convenient method, embodying the mol of the aromatic compound, and in the second step of such a method, 2 mols ofthiourea react with each mol of the dihalo diketone.

The preferred starting materials are chloroacetyl chloride and either diphenyl ether or the 'diphenyl ether of ethylene glycol I or thediphenyl ether of a polyethylene glycol containing not more than 6 ethylene groups invention, for preparing such compounds includes so Still other novel carbon compounds embodying 2, the invention are produced by carrying out a Friedel-Craits reaction between 1 moi oi the dihalide or a dibasic straight chain aliphatic acid containing'from 3 to' '14 methylene groups between the carbonyl halide groups, and 2 mole of benzene, and then haloeenating the outer-most methylene groups oi the resulting diketone to produce a dihalo diketone which can be converted to a bis-thiazolyl compound by reaction with thioure'a.

This method is versatile in that the use oi various aromatic compounds and acyl halides in the Friedel-Craits reaction makes possible the preparation oi various dihalo diketones. The large variety of novel carbon compounds produced by the reaction oi these dlhalo diketones with thiourea react wtih aldehydes to produce thermosetting resins that have widely varied properties and are thereiore suitable ior various uses.

Example 1 2 mols oi chloroacetyl chloride are mixed with 1 mol of diphenyl ether. The mixture is then added slowly to a well-stirred suspension oi 2 mols oi anhydrous aluminum chloridein 850. cc. oi carbon disulfide contained in a vessel surrounded by ice. After the addition oi all the reactants, a reddish oil is present. In order to keep the oil mobile enough ior continued stirring, the reaction vessel is surrounded with luke warm water while the reaction is continued ior 4 hours. Hydrogen chloride is liberated. The carbon disulilde is then oured oil and the reddish oil-is decomposed-by addition oi water containing, sumcient'hydrochloric acid to prevent the aluminum chloride from hydrolyzine to aluminum hydroxide; The resulting precipitate is separated and may be purified by crystallization iroin alcohol to produce a 50 per cent yield of p,p'-bischloracetyl-diphenyl other, which is a nearly white solid melting at 99-102 0. The ioregoing step is a typical Friedel- Crafts reaction. 150 grams oi thi substance-250 grams-i thiourea, and 750 oi water containing 4 cc. oi concentrated hydrochloric acid are heated on a water bath until precipitation oi the resulting hydrochloride has been completed.-; The

precipitate is separated and then dissolved in 9 solution is neutralized with a solution or sodium bicarbonate. The solid product is filtered, washed, and then recrystallized from-the methyl ether of ethylene glycol togive the p,p'-bis-(2-amino-4- thiazolyl) diphenyl ether which melts at 246-248 C. The over-all yield oi this product based on the amount oidiphenyl ether used is about 44 per cent.

Example 2 slowly to a well-stirred liters of boiling water. vAlter filtration, the hot filtered and then cooled. The solid .-oi refluxing in the first canted irom the sodium chloride. Aiterthe decan be separated. Dr ing is continued for suspension oi 60 grams oi anhydrous aluminum chloride in 300 cc. of carbon disuliide contained in a vessel surrounded by ice.

After this addltionfthe reaction vessel is sur-' rounded with luke warm water while the reaction is continued for 4 hours. The carbon disulfide layer is decanted.- and the oil that remains is defcomposed by addition of water containing sufflcient hydrochloric acid to prevent the precipitation of aluminum hydroxide. The dichloro diketone which separates as a precipitate melts at 155-165 C. 30-grams of this substance and 16.5

- grams of thlourea are dissolved in n-blltanol and heated at boiling temperature until precipitation oithe resulting hydrochloride has been completed. The precipitate is dissolved in water and the aqueous solution is neutralized with sodium bicarbonate and then boiled to cause precipitation of the bis- (2-amino-4-thiazolyl) diphenyl ether of ethylene glycol, which has a melting point oi 255-260" C. Example 3 The procedure of Example 2 is followed except that 72 grams of {3, B-dl-chloroethyl ether are used instead oi the 94 grams oi ethylene di-- bromide, and the initial product is the diphenyl ether of diethylene glycol having a melting point oi '65-'Z0 C. The procedure of Example 2 is then continued using a mixture of 26 grams of this substance with 18 cc.v-oi,chloracetyl chloride and a suspension oi 25 grams of anhydrous aluminum chloride in cc. of carbon disulfide. In the next step of the reaction, 16.5 grams of the dichloro diketone and 10 grams of thiourea are employed. The ilnal product is a bis-(2-amino-4- thiazolyl) diphenyl ether of diethylene glycol having a melting point oi flit-179 C.

Example 4 The procedure of Example 2 is followed except that 94 grams of the p, ,8'-di-chloroethyl ether of ethylene glycol are used instead of the 94 grams 0i ethylene dibrcmide. At the end of the 16 hours step, sodium chloride has separated out and the supernatant liquid is decanted liquid has been allowed to cool, an oil layer this oil by means of calcium chloride followed by distillation gives as the distillate the diphenyl ether oi trleth'ylene glycol, which boils at 240 C. under a pressure of 15 mm. oi mercury and has a melting point of 42 C. The procedure of Example 2 is then continued using a mixture of 30 grams of this substance with 22 cc. of chloracetyl chloride and a. suspension of 35 grams oi anhydrous aluminum chloride in 200 cc. of carbon .bisulfide. reaction, 30 grams of the dichloro diketone and about 20 grams of thiourea-a-re employed. The final product is a bis-(z amino-a-thiazolyl) diphenyl ether of triethylene glycol which sinters at C; and melts at C.

Example 5 A mixture of 15 of bromoacetyl bromide is added slowly to a wellstirred suspension of 40; grams of anhydrous aluminum chloride in 230 grams of carbon disulfide contained in a vessel surrounded by ice. After this addition, the reaction vessel is surrounded with luke warm water while the reaction 4 hours. The resulting solution together with sufiicient hydrochloricacid to prevent the precipitation oi aluminum hydroxide is In the next step of thegrams oi'anisole and 90 grams a assess then ured on ice. e non=ooueous product is separated from the ice and extracted with diethyl ether and the ether extract is evaporated to a residue thst is still liquid. Then after the addition of 70 cc. of ethyl alcohol, the product is cooled to the hls-bromscctirl sole, which has a melting point of C. 3.3 grams oi this substance and 1.4 grams oi thlourea are m in 30 cc. of to per cent ethyl alcohol and hosted on a water bath for 2 hours. After cool, a. precipitate oi the hydrochloride can he separated. The preci-pb tote is dissolved in co cc. of hot water contain ing iii 210. or sodium bicarbonate to cause precipitation 02 the his m-o d-thiazolyll anisole which has a melting point or 205-208" fi.

Example o 120 g. sebacoyi dichloride is added with stirring slowly to 150 grams oi enhydrous alum chloride in 600 cc. of benzene contained in a vessel surounded by ice, the addition requiring about so no The surrounding ice is then re moved and stirring is continued for 1 hour and so utes until the contents of the vessel have substantially attained room temperature. The contents of the vessel are then poured upon a mixture of 600 g. ice and 120 cc. conc. hydrochloric acid. suficient additional benzene is then added to ca all of the white precipitate to dissolve and the benzene solution is separated. After the benzene solution has been washed with a. dilute solution of sodium carbonate, the hen zene solution is dehydrated by me or calciumchloride and the bee is distilled d. The residue of slphaega-dihcnmfl octane is purificd by recrystallization from alcohol. to grams of the product and no cc. of carbon tetrachloride are heated under reflux andabout 4o ms of bromine are added one drop at a time, until no further absorption of lame occurs. Distillation is then curried out to produce a concentrated solution, which is cooled to ca cryst The crystalline product, which is purified by r with o petr'ole lisroin, melts at 83 C. and has the structural fouls E-inono on-E I 2' lo arenas oi o=chlornroiol chloride ere mixed with it urs or dipliensl ether. mixture, is then added to a wen-stir i sion. oi l5 s ot'drous aluuni chloride in so so. or cerhon con scl-ound by ice. alter zim uni n, resction vessel is ounded with lulre on water while the reaction is continued for d hours.

The carbon ide is decanted and the oil t i as is decomposed by oddition of water-con- .n m. acid to prevent the precipitation oi s1 e resulting product which separates as e preeipi tote i8 lll blilhiphawhloropropioflrl dihhenyi ether,

. then boiled to co.- precipitation ol no lois formulae (5-methyl-2-ao-d-thilsil dlnhl other which melts at 2416 C. and has the structu formula 1 Various embodiments of the invention nioy be devised to meet various requirements.

Having described the invention, l cl:

l. A novel carbon crnnound selected tr the group consisting or i .1 5 aces vine the general 8nd Ri Ai-B-AP-Rs, in which 7 bivalent radicals lee irom the one u t n is an integer from 2 to 12;; m d Rs are mono Ti and To are hivolent group oi phenylene, and substituted phenylene Al 5 not more than two inonovslent constituents selected from the group cotine oi uietlio end eiho; and s is an integer not greater :utt' i 2. do a novel carlwn a insid ho our-mull di ihei ether oi ethylene glycol. issuing the general lormule uomo i it o is.

- 3. As o novel n d, u, m rge dinhensl e oi e zoo r "or selected from the ene glycol containing not more than six ethylene groups. having the general formula f 1111!: 13K: in which a: is an integer not greater than 6.

4. As a novel carbon compound, p,p'-bis- (2- amino-4-thiazolyl) diphenyl ether, having the structural formula 111K; I EI 5. A method of preparing a bis-(2-amlno-4- thiamlyl) diphenyl ether of ethylene glycol that comprises carrying out a Friedel-Crafts reaction I between chloroacetyl chloride and the diphenyl pound selected from the group consisting of substances having the general formulae ai-fn-rkni-jn m 0 x1 X] 0 O--dn-wnm-bm-tiG in which X1 and X2 areselected from the group consisting of. Cl and Br; 11. is an integer from 2 to 12; R1 and R2 are monovalent radicals selected from the group consisting of H, methyl, ethyl, n-propyl, isopropyl, phenyl and benzyl; B is a bivalent radical selected from the group consisting of phenylene, substituted phenylene having not more than four monovalentsubstituents selected from the group consisting of methyl, methoxy and ethoxy, of which not more than three are methyl and not more than two are selected from the class consisting of methoxy and ethoxy, T1-OT2, and

-1'1-O(CH2CH2O) r-TZ 1'1 and r: are bivalent radicals selected from the I group consisting of phenylene, and substituted phenylene having not more than two monovalent substituents selected from the group consisting of methoxy and ethoxy; and a: is an integer not greater ,than 6. a

8. A method of preparing p,p-bis-(2-amino- 4-thiazclyl) diphenyi ether that comprises reacting thiourea with p,p-bis-chloroacetyl-diphenyl ether.

' i JOHN KENSON SIMONS. 

